Restore help for a noob

Let me start off by saying I have not used Time Machine so any Time Machine related answers will be redundant. So today I was changing some of my movie files from a .mp4 extension to a .mov extension. To do this I was go to the rename option and manually going to change the extension. In previous applications this has worked but to my dismay all 20 or so of my movie files have been corrupted and there is no undo button or anything for me to go back in time and fix this. I am wondering if there is some system restore like on windows I can use or anything right now to go back in time to just before I deleted the files. Please help

 

when I try to open either the .mov file or the .mp4 (after changing it back) I get "This movie could not be opened - An invalid sample description was found in the movie"

edit: Also they are sitting in the same exact folder as they were after I converted them from my HD PVR to the mp4 file extension

basically what I need to do is go back in time 2 maybe 3 hours ago